explain S0020 startup modes

[emiltin]

We need a bit more explanation of the modes here: https://rsmp-nordic.org/rsmp_specifications/rsmp_sxl_traffic_lights/1.0.15/sxl_traffic_light_controller.html#s0020

[otterdahl]

• startup: The controller starts up, performs a power on self test and performs the start-up intervals*
• control: Normal 3-light control
• standby: The controller is in dark or yellow flash mode (either according to programming or manually set)
• failure: The controller has a “major fault” defined according to 3.8 i EN12675. The controller is in dark or yellow flash mode
• test: Mode used for various tests, e.g. signal lights

Note: *) It is required that the controller always starts with a startup sequence before using normal 3-light control:

In Sweden this can be defined as:

Start-up interval 1: minimum 3 seconds, yellow flash for vehicles and bicycles Start-up interval 2: minimum 3 seconds, yellow Start-up interval 3: minimum 3 seconds, red

This is specfied in Transportstyrelsens författningssamling TSFS, chapter 2, §17 (page 4)

[otterdahl]

PR here: https://github.com/rsmp-nordic/rsmp_schema/pull/98

[emiltin]

done